The study on electromagnetic noise of satellite ground station

During the design of the satellite ground station, large amount of calculation formulas and complicated procedures may be involved, which causes the unreasonable performance and price ratio and very big waste. The authors of this paper, having comprehensively studied the link formulas and some engineering experiences on satellite receiving, and through strict mathematic deductions, have set up a new mathematic model on the antenna diameter and the unweighted video SM: D = 10(x) Where : x = 0.05; N - 0.05EIRP - 1091598564 - 0.5Lg eta + Lgd + 0.05 Delta L + 0.5Lg(T-a+ T-r) - Lg Delta f(0) + 1.5Lgf(0) - 0.05F D: caliber size (diameter)of the satellite receiving antenna (m) SN: video signal to noise ratio (dB) EIRP: equivalent wall directional radiation from the satellite to the area where the ground station is (dB . w) eta: antenna efficiency, usually is taken as 0.65 in engineering d: distance from satellite to ground station (m) Delta L: down going additional loss (dB) Delta fv: video frequency deviation (Hz) fv.: Max video frequency (Hz) F: dacentuation improving factor. Ta: antenna noise temperature Tr: HF tuner noise temperature The unweighted video SM can directly indicate the quality of pictures (which is usually required by users). Tile establishment of this formula gives a direct relationship between the antenna diameter D and the S/N. and makes it possible to draw a D-SM curve, showing that the D-SM relationship Is not a linear one. The satellite receiving antenna costs one-third of the total ground station, and the cost of the antenna is proportional to the square of the antenna diameter D. Therefor, the accuracy of antenna diameter is rather critical. The designer may accurately and quickly find out the D value by using the D-SM curve when designing a specific satellite ground receiving station, which makes the performance-price ratio of the station more reasonable and economic.